Strawberry plant named ‘Walker’

ABSTRACT

This invention relates to a new and distinct June-bearing (short day responsive) strawberry plant named ‘Walker’ primarily adapted to the growing conditions of the west central New York and other regions of similar climate. The new plant is primarily characterized by longer than broad fruit, conical fruit shape, uniformity in shape between primary and secondary fruit, reflexed calyx, dark red-purple fruit color and glossy fruit skin.

Genus and species: Fragaria×ananassa.

Variety denomination: ‘Walker’.

BACKGROUND AND SUMMARY OF THE INVENTION

I. Field & Utility Summary

The present invention relates to a new and distinct variety ofstrawberry. The strawberry variety is primarily characterized by longerthan broad fruit, conical fruit shape, uniformity in shape betweenprimary and secondary fruit, reflexed calyx, dark red-purple fruit colorand glossy fruit skin. Fruit of the new plant ripens after the plant‘Honeoye’ (not patented), similar to the plant ‘L'Amour’ (U.S. PlantPat. No. 16,480) and before ‘MNUS 210’ (U.S. Plant Pat. No. 10,191).

Test plantings in various locations at in New York, Illinois andMichigan have shown this plant to be widely adapted to differing soiland climactic conditions. It has shown cold hardiness typical tostrawberries in a matted row system when covered with straw in thewinter, which is standard procedure for this growing region.

The new plant is primarily adapted to the climate and growing conditionsof west central NY, the upper mid-western U.S, the mid-Atlantic statesand southeastern Canada. This region provides the necessary climateconditions required for it to produce a strong vigorous plant and toproduce fruit in the summer harvest season from May to July, dependingon location.

II. Cultivation Summary

‘Walker’ originated from hand-pollinated hybridization in 1997 inGeneva, N.Y.

III. Comparisons

NYUS299, the proprietary the female parent (unpatented), is June-bearingwith smaller average fruit size (8.3 g) that is medium red, firmfleshed, and conic shaped that ripens in a similar season to ‘Walker’.

NY1674, the proprietary male parent (unpatented), is a very vigorousplant with smaller average fruit size (8.1 g) that is dark red, globoseshaped, moderately soft fleshed and ripens in a similar season to‘Walker’.

Other varieties which are believed to most closely resemble ‘Walker’ are‘Honeoye’ (not patented), ‘L'Amour’ (U.S. Plant Pat. No. 16,480) and‘Jewel’ (U.S. Plant Pat. No. 5,897).

In comparison to the similar plant ‘Honeoye’, ‘Walker’ differs by thefollowing characteristics. The plant of ‘Walker’ is taller and moreupright in growth habit with greater vigor. The fruit of ‘Walker’ islarger than that of ‘Honeoye’ with a more reflexed calyx. The fruit skinand flesh color of ‘Walker’ is darker red-purple than that of ‘Honeoye’.The yield of ‘Walker’ is larger than that of ‘Honeoye’. The fruit of‘Walker’ is firmer with glossier skin than that of ‘Honeoye’. The fruitof ‘Walker’ has lower soluble solids (% Brix) and equal titratable acidscompared to ‘Honeoye’ with similar juice pH. The fruit of ‘Walker’ hashigher anthocyanin content compared to ‘Honeoye’. The harvest season of‘Walker’ is later than that of ‘Honeoye’ and slightly less compact.

In comparison to the similar plant, ‘L'Amour’, ‘Walker’ differs by thefollowing combination of characteristics. The plant of ‘Walker’ isshorter and smaller with more upright leaves. The leaflets are less wideand similar in length giving them a greater length to width ratio and anovate shape. The stipules of ‘Walker’ are shorter and less wide thanthose of ‘L'Amour’. The fruit of ‘Walker’ is smaller in size, withdarker red-purple flesh color than ‘L'Amour’. The fruit of ‘Walker’ haslower average soluble solids, higher titratable acids, lower juice pHand higher anthocyanin content than ‘L'Amour’.

The flowering trusses of ‘Walker’ are shorter than those of ‘L'Amour’.The flowers of ‘Walker’ are smaller in diameter than the flowers of‘L'Amour’ with a greater petal length to width ratio than ‘L'Amour’. Theharvest season for ‘Walker’ is more compact than that of ‘L'Amour’.

In comparison to the similar plant, ‘Jewel’, ‘Walker’ differs by thefollowing combination of characteristics. The plant of ‘Walker’ is morevigorous but with shorter stature than ‘Jewel’. The foliage is smallerin size with less interveinal leaf blistering. A pair of petiole bractsare occasionally present in ‘Walker’ and absent in ‘Jewel’. The leavesare more sharply serrated in ‘Walker’ than ‘Jewel’. The stipules of‘Walker’ are shorter and less broad than those of ‘Jewel’.

The fruit of ‘Walker’ is darker red-purple in color than ‘Jewel’ withmore recessed seeds and a more reflexed calyx. The fruiting trusses of‘Walker’ are shorter in overall length than ‘Jewel’. The fruit of‘Walker’ has lower soluble solids and higher titratable acidity thanthat of ‘Jewel’. The fruit of ‘Walker’ has higher anthocyanin contentthan the fruit of ‘Jewel’.

Strawberry plant ‘Walker’ has these distinguishing characteristics;

-   -   1. Vigorous plants with an upright growth habit and moderate        stolon production;    -   2. Trifoliate leaves with a flat appearance and gray green        undersides and ovate leaflets with greater length than width;    -   3. Longer than broad fruit, conical fruit shape, dark red-purple        fruit color, dark red-purple flesh color that is lighter towards        the center, high fruit gloss and moderately soft flesh firmness;    -   4. Reflexed calyx generally equal or smaller in diameter than        the fruit width;    -   5. Medium length pedicels and peduncles with few bracts;    -   6. Mid-season production with high yields; and    -   7. Compact harvest season.

IV. Breeding History

‘Walker’ originated from a hand-pollinated hybridization made in 1997 inGeneva, N.Y. between female parent NYUS299 (not patented)×male parentNY1674 (not patented). Both parents of ‘Walker’ are hybrids of thestrawberry genus of the species Fragaria×ananassa. Thus ‘Walker’ is ofthe species Fragaria×ananassa Duchesne. The seeds resulting from thiscontrolled hybridization were germinated in a greenhouse in Geneva, N.Y.during the winter of 1997-98. Resulting seedlings were planted in thespring of 1998 in Geneva, N.Y. The seedlings fruited in the summer of1999 and one, designated NY99-15, was selected for its attractive, darkred-purple fruit and strong strawberry flavor.

V. Asexual Reproduction

During 1999, the original plant selection NY99-15 was propagatedasexually by stolons (runners) at Geneva, N.Y. and a test planting often plants was established. Subsequently, larger test plantings wereestablished with asexually multiplied plants at Geneva, N.Y. The newplant NY99-15 was re-designated ‘Walker’ and tested over the nextseveral years in the fruiting fields at Geneva, N.Y. Further propagationwas done using tissue culture in Geneva, N.Y. to produce disease freematerial for use in further testing. Tissue culture plants were used asmother plants for propagation from stolons.

VI. Stability

Asexual propagation has demonstrated that the combination of traitsdisclosed herein as characterizing the strawberry plant ‘Walker’ arefixed and remain true to type through successive generations of asexualreproduction. All propagules of ‘Walker’ have been observed to be trueto type in that during all asexual multiplication, the vegetative andfruit characteristics of the original plant have been maintained. Allplants planted from dormant crowns or rooted runner tips have fruitedafter one season of growth in the field.

BRIEF DESCRIPTION OF THE FIGURES

The accompanying color photographs show typical specimens of the newplant at various stages of development as nearly true as it is possibleto make in color reproductions. The depicted plant and plant parts werefrom the first harvest season, approximately 13 months after planting.

FIG. 1A-FIG. 1B shows typical external fruit characteristics of ‘Walker’(A) including calyx structure and fruit shape compared to ‘Jewel’ (B) onJun. 6, 2012.

FIG. 2A-FIG. 2B shows typical internal fruit characteristics of ‘Walker’(A) compared to ‘Jewel’ (B) on Jun. 6, 2012.

FIG. 3A-FIG. 3B shows typical external color of ‘Walker’ (A) compared to‘Jewel’ (B).

FIG. 4A-FIG. 4C shows leaf margin serrations for ‘Walker’ (A), ‘Jewel’(B) and ‘L'Amour’ (C).

DETAILED BOTANICAL DESCRIPTION OF THE INVENTION

The following description of ‘Walker’ unless otherwise noted, is basedon observations taken during the 2012 growing season in Geneva, N.Y.These measurements and ratings were taken from plants planted in May2011. The age of the planting is approximately 13 months and in itsfirst harvest season. Yield observations and fruit qualitycharacteristics are averaged from data collected during the 2003-04 and2008-10 production seasons. The characteristics of the new plant mayvary in detail, depending upon variations in environmental factors(temperature, rainfall, humidity and light intensity). ‘Walker’ has notbeen observed under all possible environmental conditions. Colorterminology where noted follows The Royal Horticultural Society ColourChart, London.

Comparative Fruit Characteristics

‘Walker’ fruit, fruit production and fruit quality characteristics.Fruit characteristics are taken from the first harvest season.

TABLE 1 Fruit characteristics: Yield Total fruit yield of ‘Walker’ andsimilar varieties from 2 separate trials, one harvested in 2003-04 andone in 2008-09 in Geneva, NY. Fruit was harvested in June in each year.The plants of ‘Walker’ were grown in Geneva, NY. The other varietieswere grown in a nursery in South Deerfield, Mass. All plants wereplanted in May prior to the first harvest year for both trials. Cultivar(kg per ha) 2003 2004 2008 2009 Average ‘Walker’ 8,740 24,790 4,91020,010 14,610 ‘Honeoye’ 11,730 17,160 3,990 7,970 6,360 ‘L'Amour’ 7,09014,490 — — 10,790 ‘Jewel’ 11,160 15,440 11,270 5,760 10,910

TABLE 2 Fruit Characteristics: Weight Average fruit weight of ‘Walker’and similar varieties from 2 separate trials, one harvested in 2003-04and one in 2008-09 in Geneva, NY. Fruit was harvested in June in eachyear. The plants of ‘Walker’ were grown in Geneva, NY. The othervarieties were grown in a nursery in South Deerfield, Mass. All plantswere planted in May prior to the first harvest year for both trials.Cultivar (g per berry) 2003 2004 2008 2009 Average ‘Walker’ 10.8 10.610.7 11.2 10.8 ‘Honeoye’ 13.2 10.0 9.5 9.2 10.5 ‘L'Amour’ 11.9 11.7 — —11.8 ‘Jewel’ 10.9 10.6 — 11.1 10.9

TABLE 3 Fruit Characteristics: Color Comparison of secondary fruitcharacteristics of ‘Walker’, with standards from Geneva, NY. Character‘Walker’ ‘L'Amour’ ‘Jewel’ ‘Honeoye’ RHS Exterior red-purple 59A red 46Bred 44A red 46A Color Mature Fruit Fruit Length 3.68 4.22 3.46 3.85 mean(cm) Fruit Width 3.49 3.62 3.61 3.55 mean (cm)¹ Fruit Length/Width 1.051.20 1.05 1.08 Ratio No. Sepals/Berry 10.0 11.0 12.4 12.7 ¹Width ismeasured across the widest part of the berry, typically across theshoulders.

TABLE 4 Fruit Characteristics: Quality Comparison of 2010 fruit qualitycharacteristics including soluble solids (% Brix), titratable acidity,juice pH and anthocyanin content of ‘Walker’, with standards fromGeneva, NY. Character ‘Walker’ ‘L'Amour’ ‘Jewel’ ‘Honeoye’ Solublesolids^(1,2) 9.03 10.37 11.77 10.93 Titratable acidity^(2,3) 9.29 9.6410.93 10.89 Juice pH² 3.38 3.50 3.38 3.42 Anthocyanin 306 117 147 148content^(2,4) ¹soluble solids is estimated from % Brix with % Brix beingan indirect measurement of the sugar content in the fruit ²Averaged from3 samples on 3 dates during the harvest season. ³g per L equivalents ofcitric acid ⁴mg/100 g fresh weight

TABLE 5 Fruit Characteristics: Details Characteristic Description Ratioof length/width Longer than broad Size Medium to large Predominant shapeConical Difference in shapes between Little to none primary andsecondary fruit Band without achenes Intermediate width Color of maturefruit Bright to dark red Evenness of color Very even Glossiness StrongInsertion of achenes Level to slightly recessed from surface Attitude ofthe calyx segments Somewhat reflexed up Size of calyx in relation to 2.3cm to 4.0 cm fruit diameter Adherence of calyx (when Strong fully ripe)Firmness of skin Moderately firm Color of flesh Dark purple-red withlighter ring (red- purple 59A to red 44A in center) Distribution of redcolor of Throughout the flesh with the darkest flesh the flesh aroundinternal margin and lighter towards the center Hollow center Moderatelyto strongly expressed Seed color Medium yellow-green to dark red-purple(yellow-green 151D to red-purple 59A). Time of flowering (50% of Mediumto early plants at first flower) Time of ripening (50% of Medium toearly plants with first ripe fruit) Type of bearing Fully short dayresponsive Avg. number of achenes 240 per fruit Achene position Indentedin the flesh so that the upper surface of the achene is even to slightlyextruded above the flesh surface Presence of hollow core Common, oftenwith pithy flesh within the space Hollow core length 5 to 15 mm Hollowcore width 5 to 7 mm

Plant Characteristics

‘Walker’ plant characteristics. Plant characteristics are taken from afully mature mid-season plant.

TABLE 6 Plant Characteristics: Comparisons Comparison of plantcharacteristics of ‘Walker’, with standards from Geneva, NY Jun. 22,2012. Character ‘Walker’ ‘L'Amour’ ‘Jewel’ Plant Height mean (cm) 26.031.9 27.3 Vigor¹ 8.0 8.3 5.0 Canopy density¹ 7.5 7.7 7.0 ¹Rated on ascale of 1-9 (9 being more vigorous or dense) in mature replicatedplots.

TABLE 7 Plant Characteristics: Details Characteristic Description SizeMedium Habit Upright Density High Vigor Strong

Foliage Characteristics

‘Walker’ foliage characteristics. Foliage characteristics are taken froma fully mature tri-foliate leaf during mid season.

TABLE 8 Foliage Characteristics: Comparisons Comparison of leafcharacteristics of ‘Walker’, with standards from Geneva, NY on Jun. 22,2012. Character ‘Walker’ ‘L'Amour’ ‘Jewel’ RHS Color green 137A green137A green 138A (upper surface) RHS Color greyed-green 191A green 139Cgreen 137D (lower surface) Terminal Leaflet Length 7.4 8.4 7.5 mean (cm)Terminal Leaflet Width 5.7 8.5 7.6 mean (cm) Terminal Leaflet ratio 1.290.99 0.99 (L/W) Petiole Length mean (cm) 21.1 22.8 19.9 Serrations/Leaf26.9 22.3 18.3 Stipule Length mean (cm) 1.6 3.5 3.0 Stipule Width mean(cm) 0.6 0.8 0.8

TABLE 9 Foliage Characteristics: Details Characteristic DescriptionColor of upper surface Medium to dark green Color of under side Mediumto light grey-green Shape in cross section Slightly concave Interveinalblistering Light to moderate Glossiness Low, flat coloring Number ofleaflets/leaf Generally three Terminal leaflet size Small to mediumTerminal leaflet - length/width ratio Longer than broad Terminalleaflet - shape of base Cuneate Terminal leaflet - shape serrationsAcute Petiole - pubescence density High Petiole - stipule color Light tomedium yellow-green (yellow-green N144C) Petiole - anthocyanincoloration of stipule Slight blush of Red 45D Petiole - attitude ofhairs Strongly upward towards leaf Petiole - size of bract leafletsSmall Petiole - frequency of bract leaflets Approximately 10% of thepetioles Avg. number of leaflets 3 Venation pattern of leafletsreticulated

Flower and Inflorescence Characteristics

‘Walker’ inflorescence and flower characteristics. Inflorescencecharacteristics are taken from a fully mature plant during full bloom.Flower characteristics are taken from a secondary flower during midseason at full maturity:

TABLE 10 Flower and Inflorescence Characteristics: ComparisonsComparison of inflorescence and secondary flower characteristics of‘Walker’, with standards from Geneva, NY on May 10, 2012. Character‘Walker’ ‘L'Amour’ ‘Jewel’ Fruiting Truss Length¹ mean (cm) 21.6 32.320.9 Corolla Diameter mean (mm) 35 36 31 Calyx Diameter mean (mm) 33 3334 Petal Length mean (mm) 14.8 15.4 14.0 Petal Width mean (mm) 13.3 13.613.3 Petal L/W Ratio 1.09 1.13 1.09 Petals/Flower (mean) 5.8 5.1 6.3Sepals/Flower (mean) 10.0 11.0 12.4 Petal shape obovate Petal RHS colorwhite 155C both surfaces Shape of Apex rounded Shape of base cuneateShape of margin entire (not serrated) ¹as measured from the base of theprimary peduncle where it attaches to the crown of the plant to thefurthest berry.

TABLE 11 Inflorescence Characteristics: Details CharacteristicDescription Position relative to foliage Even with canopy Fruiting trusslength Medium

TABLE 12 Flower Characteristics: Details Characteristic DescriptionColor White (white 155C). Size Medium to large Size of calyx relative tocorolla Equal to smaller Relative position of petals No overlap whenfully open Petal length/width ratio Longer than broad Petal shapeObovate Sepal RHS color Green 137D Avg. sepal length 8.5 cm Avg. sepalwidth at base 3.4 mm

Pest reactions: It is known to be moderately resistant to thetwo-spotted spider mite and susceptible to aphids and flower thrips. Itis susceptible to leaf spot, scorch and blight. It is resistant topowdery mildew. The susceptibility of the new plant to any of the viruscomplexes of NY has not been determined.

We claim:
 1. A new and distinct strawberry plant cultivar as hereindescribed and illustrated.